SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f3e0c02b25a8822440b75ce3cdc4d6382326c4075131d1db32874b2d0558d2f' 
  AND token = 'RiWd8rXpvbk88GOTh7xPenhxoK84vCKzmxMSEbsWFMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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