SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44792ba56079a649365a0c1930c6ab9b2b43ad068ad82088136466c85ff03ec9' 
  AND token = 'eT3DvoMX+gMDzdoUqr/GOfnHne+CPWpruUQvSZh/PM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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