SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f41b72764748e273ccd56c84969f022c8daab841217468de9d590b1e0e853c' 
  AND token = 'UzAhh/vvAwKCKiDgx6/H28yYeExotYhgYa8AI+Gi81M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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