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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '768bc57fcf5ae4ebd7add01d01062adaeb3a7908bddf24619be0d258e5e8adad' 
  AND token = '/mg4NFnCJKTA8emfVdiSI4S3Vxq2+DUlIzo9XnYwOdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}