SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a94bb3e645f789d0fa561ea8006b35889bf2d7a0433af063eccebba181ac3d56' 
  AND token = '+wWmA9tqqYFuhGPVZedGFzP8Ps+jBqErt8NY/VVbKTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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