SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5715cd9cdf55d33ec17daeebefd8b4baa7a95aad016999cd57b6d397bc552f6' 
  AND token = '6pLiGLEyDZtVR6ZJMkPmRNmMCWIFKz58ToM1IxQKwjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}