SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f2797436ce8fd868899a79d3df50789f6ea18ed1f326158e8400801edf74709' 
  AND token = 'Znk3a/gW8qDOIohJhigOod+fiA9CGa3Hag65bZ7l8mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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