SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '242cda252b82e7ad8cf71df039fc9cedec0c73ebf8bee6e1b1e41f8268405360' 
  AND token = '9iaTGluK6X+bGpgohEGZkiIsN0ESZQMl7UnP02uzC3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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