SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5023fa44d984aba70c8256580a3912d40c69ffc102cccabcc04851684a0ed26' 
  AND token = 'MbhhXTNLtU+MwjlLPt50KKv/o/lJASx0nlk7L3mpPGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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