SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b1af8064b578cd069ae4befc6a9ae345b22820288a2327190f320449a4d9e57' 
  AND token = 'znm04cpa0OjDSBu8v4D1k57+BfRpd4dNS5HK6ZxU4ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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