SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '315f4ee793abc9926f6bfee3f7951c950b8c2b266787d0d25d9c5453566bcc2f' 
  AND token = 'XNLTKMAks9FtbsZaBnYujlyhkGQvd+ka5WQ2/lZ3imo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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