SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9651d56005f34ead8a21b39d9d3e434c0357c051165139a7ba39a78df05bdc2' 
  AND token = 'kiBBHys0sGAKmPsF8a9djPheWuBQja5lJGWP9TkorH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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