SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3a56466f96d995fdcac5622df41667bb23a79c18bd5b835b8f426ad5d96bb71' 
  AND token = 'Z7NwmnmEIlLPZQQPvKVLpaAP1aCj7y1Y7s1CsIlALaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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