SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '500791d0aa76e3c87a5a0dd2f3161e1dafb9d395c470273e45c5bedc1ec842c5' 
  AND token = 'p5zKKapjOKgkGlaMF4JePeQpnKau2Zvpr0+XWw1ktDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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