SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54df9bbf9442958125950a0319c62217623456ff171d1b6e658ee8d652f7e661' 
  AND token = 'c0UjkYFBo/7pyypKJFLG++9usps6q1JZFTdDgR38eZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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