SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4611e1523bdb79694466be7a2f369aaa503774a8751bf39090c76b2b806ba18' 
  AND token = 'evJMGOVXsg63bHMA9x7SfqwcuCC6gtdKrKYzimYnX38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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