SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b98529d283817e2c5382319fa9a06075c7f057dfe41871c99ffa6c04334d2a0' 
  AND token = 'jxRUB4wg0wzKElNhKi8TPyfDFvdObk3/DMp1soyBHGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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