SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8a6248aa110e92caafcf22270a03747c8dc41dafef3bae2c85868eb80de55bf' 
  AND token = '8Lv4zaXlkL6OstPD8yLKanaF+vinFYon0zxSTmp4icw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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