SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afc6470ca41746359fd9492d380a2e03d46be68b08663ac0507d0e71d5d2242d' 
  AND token = 'ORJx1qo5P7Sy2t0NimCDzA8Z+gTy0p/jmf0TPVz16uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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