SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b28cc00b181714ea98e97e6a8d97e59d1b25ad748b157f31e38dd718f308c3a6' 
  AND token = 'bm8PYPDlnrR+dz3pGJHEoVE4nWS2BcLyzEyMOBkvVx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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