SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da9d8b5b021ad4adb5a2490a659fd9971244846934536f29a93e8bf1d6b7dfe5' 
  AND token = 'Z5WLLUn+z/H6HMppITWqC4fIwZKTGFfA+qX/+2ZWMwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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