SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940d9445780b6511dc694bd1e692a41b0972c039f3de4b28151340adeb23dab0' 
  AND token = 'h4H58WOXJAJVLCe5HlMgqW0LUI+MCAPtkFC18JWM+iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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