SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8a00fba3fff3647c293b2ef55c1ef3dc0b6e0339841b3205048c8385167087' 
  AND token = 'yXe+Mk9VfE1KJKFnrqyAnU2sei4GwxrGmklyB660Dws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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