SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '273fa891fd6b593514ff6854c74abe68b7721e04cb7c672d8a3d105bb915a8b2' 
  AND token = 'nFwG/gYQ2bYxcSsoz1ZVu9V4QooCZdm/hziBdL8vifs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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