SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337ce131bea5b21e0bb3a1364a1a93d2c65b38649a3ea28c46e5d592988a6d4a' 
  AND token = 'nHblADZlYkz/IyuwWjPxJLQeNSbmSKfhNrNG5HyAlmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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