SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4391c0ca955152c7ba5005650757dc20e011d660f9534fff1b101697d006fbb5' 
  AND token = 'ZdETr1HvlHe3m6lqQ0uVL1HW+5KjoZ/gSEtS3AxFRTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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