SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4645c279aad572f8fb0c4078eebc9db75ab482213a0be3d5d81afdab0929204a' 
  AND token = 'lUeZ/cn7vBlI/NVo9N2D2U6lnN5B7otq8XyD7f5QZ7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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