SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8810628e55143257fb2544c1cea5edc41232c738749bb01614c7941ed6dcab27' 
  AND token = 'JTA8oTgMHVb1tLYixR+7EKWS3VZgUMdLwTTvHex7kMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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