SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f31432e6eb8f4becac9faeba46240fa2b1cd4849f47a6f4f27fb9a7a3b510d7' 
  AND token = '4xky6KaN2ofBmvWH3NPIdNosDT4FqCrbCCEoYzBfj0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}