SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcfe9fc2d881c2c8403385bf9e8324a351e1b20dca00ad5b895ce21b5aa4dd54' 
  AND token = 'TE0CYtuOD+pyn15pQ92lV1EzvITW9UemL2P8CA4jP7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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