SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '28adc4f96cc777f4e01e4921f55d159ff2b4a2f6555965a40ad7665fd3bb3c2a' 
  AND token = 'P5DAB/yjltTo+hOOzygyi4WhgjDllF1QiphGWsFiYCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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