SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453c5946c1e0a1166295aad5d49afd2825672d59833dda1407fca2c50bb20012' 
  AND token = '7Jt6C1Pw9D7zuP5BZeENZsAcZnAt0q/aG9vhxM+HQXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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