SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c36d521b217e9a8be86751ae2daabad3671a97bd1d61d8d741a03044b8218192' 
  AND token = 'syDhwkjMYhsEMZJUWB+oXRJjyYYsteBfXCuoB5GJvdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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