SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f710d662d685aea319be569de1c64022f781f8520f0953004fbd0a85b281498' 
  AND token = 'Y2Zft34uqxMw4UwaKXJY4qTNSi/Ap1RsaFiT9H5WPGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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