SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ad84e5081323b4588f96283cf0401d3c54c3d3cc9b0ddb282e52cbcbd5e3a2' 
  AND token = 'FIpIFBYtXCoejgq9lG6v5/lyf6epKZeu9/Np3aYRsao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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