SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7271bc3dfd2517495e2e46c18baba8175d37f681312ae5ebfa822a59695add93' 
  AND token = 'r+NOXb9UQraa53rgZdxKBxQo52aPtQ8bfWmK1LUoGew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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