SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cace5850244d241b3252fe84721289396f3ce31af489d74c7709e5c76f1ffb5b' 
  AND token = 'v3rMm2JOB8h/q34ilfaM+UmLVQmQ6Ltza42APuXoqqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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