SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb625b04c482c4ef3386884e53f48528244bcf42f3baaec688527ed87b59bed' 
  AND token = 'mGxKFelJCUbTak1cNopdb2MYJnpkQNQ+sspmQchtZ3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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