SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4336cf533ff9f88221922867afee7c18fcc470ccfcdafeab822893de75f318' 
  AND token = 'v4gHtst+nQ7GRyFbVXDOVzzlv7qju8OB9VKICJ5PNN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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