SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f2832f63efc3e4ee7d3c8305fd92e8917c5cfc947254578eeeda953622008db' 
  AND token = '8Pd1Sp6w0yfE5UweNe0RPBa3mD6LxkFULLdSZn8Wdmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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