SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb81e0ea5b9bc951ea64948856f6110b4b6c30b9bb85e0a979c46f7b47cc7979' 
  AND token = 'MtPS3lGAUAY9CD+2UEhsl0fKLsifogvZkjlwGVB7/zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}