SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9928f14b83586cbbeca20a0ca727cd6bc34bafb470cf697ccddf221c7a16299d' 
  AND token = 'qVMNyjUZsusLJlcX5pGSfneBTafCqWRPezUdar7KfjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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