SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f88c6755c3d1450e304a8a32aad2ea1ace5b171c2c087eee0ffeac9ad17d0b61' 
  AND token = 'SSrW+3QKcxerKX32FdZuZzJNykfSnpIRx59ZVLIGPxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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