SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275f5c41d716e35c4d946a313160721ff4ea5ff610fb8ce68a61a5e8c8e98b2f' 
  AND token = '4zSTL1Ve3owCwFKlcUpPEF+HXWTxaOtoFeDQpbdRcgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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