SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f99a466f6bcb6455202f9cb3a267e54d9873b6f3ff2add68b1775563eb09bac' 
  AND token = 'LeuS1tUkBj0lCGcMtYZQdP3E49/87bry2kiecFi7Vwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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