SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fe5a04e9368ae1fc0398c28da9760b121f5930b70fbb219ec94806aa44042ba' 
  AND token = 'LBXfKk/OiGcAxPWxvW6Vv9Jy7KhjWpMeR+DS03BBR/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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