SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fa3f919ca48f4747b7c56b864c5d351d7542edb439392af6508eb6f089aee87' 
  AND token = 'LBel8UFqO/8Gm2MqanOfyVwf7YhiH/LMeIDVpIZdHZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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