SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd275e51f2f491983e0a5722d22f11a741d5e3306a2310888c614808c994b8c4' 
  AND token = 'wzhDPXhhPzQVA7UZR51olNT3cuhfFCKOejaQ2YSTn3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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