SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e4f2c30670484cea89e05860898464869b92783cd58674be2bc3fd839d7ebb3' 
  AND token = 'HSYmGjYCGY/RzH7kDfGBY5dfVDZnaHgHwMimS6XFDAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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