SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc30a0f185adf65f4f1a1fc38156dac15d28fd09c60bd69487605b8384649a62' 
  AND token = 'GFD+OWCYJ2IzupsUZzZUpXcvNEB450hA71s6fkfvRww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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