SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b6a9b3198ad25ffb0671ad4808b162d8c8d553621b365e2ac4a4706a4433c78' 
  AND token = '6L6sKHF9gZz3nYOtXrGBmPQeEMrepk4hFXVU7XOwDc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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