SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26921a2451d79f0a2678e4b5855545ad45fbb27459f5ee243efa30dcc575222f' 
  AND token = 'sJmgT91z+/eLMWYgyElUox5zy1wZntJNoVNFQY/xnc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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