SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'faaf27d4fb3128b8a188dd5b9fee243b82146b8ff7d3b4a09c2041436cedc336' 
  AND token = 'JBFwu7ijfV1nVp4a5zIYcMK6ARqgnJCWvy5aOuKS/e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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