SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fc5ab1b2865ad64f6a0030cc057ad7590db6c3dc6095b4ad76381896af5e6e8' 
  AND token = 'TJCCZI1gPjyayvCzAfD4OC3bMUfLk5V/8flQ1dRTpPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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