SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4b5fc2cd2232145430b0ec15d7e20313e673795ab964cea7c12c8c8f4dc0c2a' 
  AND token = 'Y8eYDfnHhGofkKzmKHJwH/RM19p6A6Wbu+ftAVgbMuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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